import tkinter as tk


window = tk.Tk()
window.title('hello thinter')
height= window.winfo_screenheight()
width= window.winfo_screenwidth()
window.geometry('400x300+%d+%d'%((width-400)/2,(height-300)/2))

m1 = tk.PanedWindow(showhandle=True,sashrelief="sunken")
m1.pack(fill="both", expand=1)

left = tk.Label(m1, text="left pane")
m1.add(left)

m2 = tk.PanedWindow(orient="vertical",showhandle=True,sashrelief="sunken")
m1.add(m2)

top = tk.Label(m2, text="top pane")
m2.add(top)

bottom = tk.Label(m2, text="bottom pane")
m2.add(bottom)

window.mainloop()